Valen Biotech, Inc. has developed a novel fluorescence in situ hybridization (FISH) method, called MicroFISH, that directly detects nucleic acid targets with a patent-pending system of short, synthetic probes that effectively bind multiple long DNA-based reporters to a small specific sequence. The structural advantages of this modular system greatly enhance signaling, specificity and speed compared to standard probes, and provides variable signal strengths and colors. The system can detect single copy genes in situ as well as point mutations or sequence variations that identify genetic disease, cancer or species. This application applies this system to mycobacteria of clinical importance, using M. tuberculosis and M. avium RNA targets to show the feasibility of direct diagnostic tests for infectious diseases without amplification. Phase I will test this system in microarray format so that different nucleic acids can be simultaneously compared using two or three color fluorescent detection. Testing then proceeds to mycobacterial cultures with fluorescent microscopy. Phase II extends testing to sputum smears and to the development of commercial MicroFISH assays for the major mycobacterial species. [unreadable] [unreadable] Tuberculosis (TB) (caused by infection of M. tuberculosis) is globally the most important cause of death from a single pathogen. Diagnosis primarily occurs by microscopic analysis with acid-fast stain and by growing cultures for biological tests. Staining is quick but uncertain; culturing is definitive but slow. Developed countries now employ nucleic acid amplification-based tests, such as polymerase chain reaction (PCR) or DNA transcription-mediated amplification (TMA) technology, for fast, reliable results. The applicant organization's system would be rapid (less than two hours), highly sensitive (equal to PCR), inexpensive (less than $4 per unit cost), and simple to perform (uses standard equipment). This would make the test ideal for developing countries that need rapid, sensitive tests, but do not have the resources for amplification-based technologies. The worldwide market for TB testing is $900 million with amplification-based tests constituting approximately one-third of the total. Based on a survey of potential customers and diagnostic company professionals, the market potential of the Valen Biotech, Inc. system is over $100 million. Successful achievement of developmental milestones could push the potential significantly higher. [unreadable] [unreadable]